use std::io::stdin;

fn get_line() -> String {
    let mut line = String::new();
    stdin().read_line(&mut line).ok();
    line
}

fn main() {
    let line = get_line();
    let line = line.as_str();

    let mut result = 0;
    for i in line.chars() {
        if i.is_numeric() {
            result += i.to_digit(10).unwrap();
        }
    }
    println!("{}", result);
}